Fusible link.



G. I. ROCKWOOD.

FUSIBLE LINK.

APPLICATION FILED AUG. 14, 1011.

Patented Ja11.20, 1914.

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if 20 rney rrn GEDRGE I. IROCK'WOOD, OF WORCESTER, MASSACHUSETTS.

FUSIBLE LINK.

asagna.

Specification of Letters Patent.

Application filed August 14, 1911.

Patented Jan. 20, 1914i.

Serial No. 643,883

To all whom it may concern:

Be it known that It, Gnonon I. Roonwoon, a citizen of the United States, residing at Worcester, in the county of Worcester and Commonwealth of lVlass-achusctts, have invented a new and useful Improvement in Fusible Links, of Whichthe following is a specification. l

My invention relates to fusible links arrai'i'ged to form part of a tensile support and to remain unbroken except in case of fire. lhe tensile support of which the link forms a partmay be employed in holding open fire proof doors or shutters between the different rooms 01 stores or warehouses, or for similar purposes, where a door or shutter is designed to remain open except in case of tire. The fusible link is arranged to yield at a predetermined degree of heat by the melting of the fusible material forming part of. the link and to allow the door or shutter to close. The purpose and character of the fusible link shown at present is similar to that shown in the Letters Patent No. 911,162, issuedto me February 2, 1909; and theobjects of the present improvement are to construct a link composed of separate members fashioned by fusible solder, with a portion of thecontacting surfaces of said members arranged at an angle to the line of tensile strain, so that the members in separating under the tensile strain when the solder is melted will separate upon a line at an angle to said tensile strain; to apply the attaching solder in such manner that the members in separating will exert a shearing out upon it on a line transverse to the line of tensile strain by surfaces at right angles to each other. Thisbrings the force of the tensilestrain upon the solder against the line of adhesive force, so that the members will not separate under the tensile strain until the solder is sufficiently softened."

' In my improved link I provide abutting surfaces at an acute angle to the line of tensile strain, and I hold these surfaces in contact by solder applied to the members at a dili'erent location than at the position of the abutting surfaces. \Vhero the solder ap plied, the surfaces of the separate members are approximately at right angles to each other, and a separation of the members under the tensile strain is at .t line parallel with the surface on one member to which the solder is applied and approximately at right angles to the. similar surface on the other.

i attain these ob ects by the mechanism illustrated in the accompanying drawing in which i i Figure l is a plan \lOW of my improved link. Fig. 2 is a central longitudinal section. Fig. 3 is an end view. Fig. l is a transverse central sect ion.

Similar re t'cronce characters refer to similar parts in the dill'erent figures.

In the drawings, 1 denotes one member of a fusible link, formed from a plate 2, having at the outer end an eye 3 to which a cable may be attached. The other member l is also formed from a similar plate 5 with an eye 6. At the ends of the plates 2 and opposite to the eyes 23 and t3 the opposing surfaces 7 and S are arranged, which, in the present instance, comprise on the plates 2 and 5 transverse inward V-shaped bends at an acute angle to the line of longitudinal tensile strain exerted upon the plates 2 and .3 by the cables which may be inserted in the eyes 3 and 6. These transverse \l-shaped bends, as shown in Figs. 3 and l, do not extend to the edges of the opposing surfaces which ar arranged upon the planes of the remainder ol' the plates. The transverse V-shaped bond 10 in the plate :2 is matched. by a similar bond 9 in the plate 5, which is designed to rest upon the upper side oi the plate As long as these Vshaped bends l) and 10 are in engagement any longitudinal strain applied to the plates 9 and 5 will have the eil'ect of separating directly the opposing surfaces 7 and 8, and this direct separation will continue until the V-shaped bonds are suilicicntly far apart for the bend 9 to slip by the bend 10, causing a separation of the members of the link. In the present case this direct separation between the plates 2 and is prevented by rows 12 and 12} of fusible solder placed upon thc edges oi the upper surl'aceot the plate 5 beyond the ends of the bend S). These rows of solder extend inward on the plate 5 only a short distance and leave without a covering of solder the \i-shapcd bend 9. The edges of the plate 2 are turned upwardly forming flanges l-t and 15 preterably at an oblique angle to the plate 2. The rows 12 and 13 of solder contact with and are soldered to the edges of the plate 5 and the turned up flanges l4 and 15 between the obli .1 heat the u YOfi -ziihfi plate 2. The 0' posingsur f-aces 7ia nd are also preferably, unitedbya slight'covering -16 of solderl r.

Any tensile strain exerted upon-the mem--- .bers 1 and-A W111 .bt iocking of the V-shaped bends Q-"andiIO until.

eyes the plates 2 and resisted by the inter-- fthe fusible material 12, 13 and 16 is softened the required degree of heat. 'When'this' fusible material. has become softened, the "16 force offthe-tensilestrain tendsjto separate parallel with the plate 2. A portion or the solder 12fand 13- upies thew-shaped space 0%.: upturnedflan'ges. 14 and! 15' and the 3 downwardly turned ,portion of the plate 5, and extends over theedges of the plate 5.. A's the solder l2and 13 is softened by heat, the flat edges of. the plate-5 under lying the solder will be lifted by the movement of the bends 9 and 110 relatively 'to each other, causing. a displacement of the soldier. The movement apart of the plates 2. and 5 tends to overcome the adhesion of the solder in the rows 12 and 13 by-ashearing action, 'the'lifting of thelate fi shearing the mass of solder resting t ereon, from the mass of solder"attached to the flanges 14: and 15.

When the device :is subjected to the action "rows-.12 and 13 of solder, and the release of i the plates 2 and 5- is accomplishedwhen the solder in the rows 12 and 13 is sufficiently softened to yield tothe shearing strain exerted by the separating movement of the plates 2 and 5. v, y

I have found by experiment thatthe pres determined degree of heat is more accurately gmeasuredby the resistance of a fusible metal a'shearing strainthan by its direct adhe- 5d.

sion'. My present invention is designed .to

construct a'fusible link adapted to be released by a shearing" strain rather than by the resistance of a fusible metal to compression, as in the link forming the subject'of my Patent No. 911,162,- or by thedirectadhesive force of a fusible metal I am aware that interloekin surface ofplate 5 and v i thej11nder sur ace of plate 2' are fully exp o'wd, as well asthefouter surfaces of the held,

msahttogether by a fusible material have been ema sployedinthe construction of so? called fusible links and I do not claim such broadfly.

By my present invention, I am able to em: ploy a retaining mass of solder, arranged to be sheared apart, and Ia'pply the solder di-- v rectly to prevent the lifting of the plate 5 by the movement of the oblique surfaces of the transverse bends 9 and 10 'over each I "other.- A smallresisting force exerted by the roWs o-f solder 12 and 13 is enabled toWithstand a powerful longitudinal strain upon the plates 2 and 5. jI .claim,-

tensile strain, comprising two members, one

ing beyond the edges of the other member,

1. A 'fusi-ble-- link adapted to receive a j of said members having side flanges extendi said members having opposing surfaces, oblique to the line of tensile strain, and means for .holdingsaid oblique surfaces in engagement, said means comprising a material fusible at a predetermined degree of heat, said material being attached tosaid side'flanges and to'the adjacent edges of the other vmember.

2. A fusible link comprising tWo members adapted to receivea-tensile strain and hav'-' ,ingopposing surfaces oblique to the line of tensile strain, one member having free, edges turned at an oblique angle to form diverging side flanges extending beyond the edges,

of the other member, and fusiblematerial arranged to contact with the inner'surfaces of said flanges and the vadjacent edges .of

the other naember;

3.;A fusible link comprising two plates 7 adapted to receive a tensile strain and hav-' ihg opposing surfaces oblique to' 'thevllne oftensile. strain, one plate having free :edges bent across and beyond the' plane of the other plate-and fusiblematerial connecting 1' r the exposed surfaces of the edges of the lat- 'ter plate and said bent edges.

" 4. A fusible link comprising tvvo plates;

having engaging transversegv-shaped bends, 1

extending partially across the-plates, with one of said plates provided with oblique 'flanges extending beyond the edges of the other P a and le material attached-to the inner sides .of-{said flanges I and to the outer surface of theoth'er plate.-

. E-.1- gBooKWoonQ Wit se ZPENELLOPE 'Comsnnsaon, 

